VTOL aircrafts such as helicopters found applications in both military and civilian markets. For example, a kind of VTOL aircrafts generally called tetra-propeller aircrafts are made for entertainment purposes. However, tetra-propeller aircrafts are by no means limited as toys or remotely controlled models. Tetra-propeller aircrafts may be used for survey, surveillance, aerial photography, etc.
Many existing tetra-propeller aircrafts comprise many components distributed through the aircrafts. Exemplary components include carbon fiber plates, carbon fiber rods, and aluminum alloy plates. These components usually have complex shapes. The number and the complex shapes of the components render these existing tetra-propeller aircrafts less crash-resistant, less deformation-resistant, less wind-resistant, less fatigue resistant, less agile, and/or less controllable (especially when performing complex maneuvers).